Most bacterial infections arise from attack of bacteria on mucous membranes. For establishment of such infections, the initial ability of the bacteria to adhere to epithelium surfaces is of the greatest importance. The infectious capacity of gram-negative bacteria (for example Escherichia coli) is thus directly related to the ability of the bacterium to adhere to epithelium cells (Jones, J. G., Ref. 1). E. coli bacteria adhere more readily to epithelic vaginal cells from women showing a tendency for urinary tract infections as compared to epithelial vaginal cells from healthy controls (Fowler et al., Ref. 2). Correspondingly, investigations both in vivo and in vitro have shown that a larger number of bacteria adhere to periurethral epithelium cells from urinary tract infection-prone girls as compared to the corresponding cells from healthy controls (Kallenius et al., Ref. 3).
The importance of carbohydrate structures on cell surfaces for biological recognition (i.e., receptors) has been recognized including the recognition of the bacterium by mammalian cells (Ref. 1) necessary for adherence thereto. Studies have shown that the adhesion of several uropathogenic E. coli strains to periurethral cells is correlated to the ability of specifically agglutinating human erythrocytes (Kallenius et al., Ref. 4). From this the conclusion can be drawn that which is some substance, possibly of a carbohydrate character, present on the surface of human erythrocytes, is the receptor which is recognized by such urinary tract pathogenic bacteria and necessary for adherence of the bacteria to the surface thereof.